1,720,961 research outputs found
Improved methods for surveying and monitoring crimes through likelihood based cluster analysis
Full text linkThis paper focuses on a development of a classification model that gives an accurate placement of regions into classes of the relative risk of crimes over time. The analysis was based on statistics on the cases of burglary and murder from 13 regions of Namibia for the period 2002 - 2006. Since crime statistics are counts, they are often contaminated by heterogeneity. The effect of population heterogeneity in the crime counts in particular makes comparison of crime risk across regions using traditional methods of classification impossible. As such a method for standardizing crime counts was introduced and models for modeling population heterogeneity proposed. In particular a mixture likelihood approach to clustering by McLachlan and Basford (1988) which was further extended for covariate effects was used. This is due to its ability in identifying important clusters and in mapping the relative risk of crime onto the study regions via the maximum a posteriori (MAP) method while inference was done via the EM algorithm of Dempster et al (1997). The result shows that the space - time mixture model conducted under non - parametric form gives a good account of the relative risk of the two crimes over time, while both space - time mixture and covariate adjusted space - time mixture models points to a 3 risk classification of the regional relative risk of the two crimes namely high, medium and low risk class respectively
Monitoring murder crime in Namibia using Bayesian space-time models
Full text linkThis paper focuses on the analysis of murder in Namibia using Bayesian spatial smoothing approach with temporal trends. The analysis was based on the reported cases from 13 regions of Namibia for the period 2002–2006 complemented with regional population sizes. The evaluated random effects include space-time structured heterogeneity measuring the effect of regional clustering, unstructured heterogeneity, time, space and time interaction and population density. The model consists of carefully chosen prior and hyper-prior distributions for parameters and hyper-parameters, with inference conducted using Gibbs sampling algorithm and sensitivity test for model validation. The posterior mean estimate of the parameters from the model using DIC as model selection criteria show that most of the variation in the relative risk of murder is due to regional clustering, while the effect of population density and time was insignificant. The sensitivity analysis indicates that both intrinsic and Laplace CAR prior can be adopted as prior distribution for the space-time heterogeneity. In addition, the relative risk map show risk structure of increasing north-south gradient, pointing to low risk in northern regions of Namibia, while Karas and Khomas region experience long-term increase in murder risk
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Surveying and monitoring crimes in Namibia through the likrlihood based cluster analysis
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
Recommended from our members
Resident Student Perceptions of On-Campus Living and Study Environments at the University of Namibia and their Relation to Academic Performance
No full textThis study measures resident student perceptions of on–campus living and study environments at the University of Namibia campus residence and their relation to student academic performance. Data were obtained from a stratified random sample of resident students with hostels (individual dormitory) as strata. Student academic performance was measured by grade point average obtained from the university registrar. Student perceptions of living and study environments were obtained from a survey. Inferences were made from the sample to the population concerning: student perceptions of the adequacy of the library and campus safety, and differences in perceptions between students living in old-style and new-style hostels. To relate student perceptions to academic performance, a model regressing GPA on student perception variables was constructed. The principal findings of the analyses were that (1) Student perceptions do not differ between old and new hostels; (2) There is an association between time spent in the hostel and the type of room, ability to study in room during the day and the type of room, ability to study in room at night and the type of room, time spent in hostel and number of times student change blocks, ability to study in room at night and availability of study desk in room, ability to study in room at night and availability of study lamp in room, effectiveness of UNAM security personnel and safety studying at classes at night and also between effectiveness of UNAM security personnel and student perception on whether security on campus should remain unchanged respectively; (3) Mean GPA differs with respect to the type of room, ability to study in room during the day, time spent in hostel, number of times student change blocks, current year of study, time spent on study, students who are self-catering, sufficiency of water supply in blocks and also with students who are enrolled in Law and B.Commerce field of study and with students receiving financial support in the form of loans. (4) The variables found to be significant in the regression model were Law field of study, double rooms, inability to study in room during the day and self-catering respectively
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
